Dowser control mechanism for motion picture projecting machines



Jun 6, 1931- J; -T. FEWKES 1,310,348

DOWSER CONTROL MECHANISM FOR MOTION PICTURE PROJBCTING MACHINES Filed June 4, 1928 2 Sheets-Sheet l TIE--L.

WITNESSES: INVENTOR:

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J TTORNFY June 16, 1931. .1. 'r. FEWKES 1,310,348

DOWSER CONTROL MECHANISM FOR MOTION PICTURE PROJECTING MACHINES Filed June 4, 1928 2 Sheets-Sheet 2 In E- 1M 'liNTOR:

Patented June 16, 1931 UNITED STATES PATENT OFFICE v JOSEPH T. IEWKES, OI PHILADELPHIA,

PENNSYLVANIA; ASSIGNOB 'ro BENTZB'! mm column CORPORATION, OE PHILADELPHIA, PENNSYLVANIA, A CORPORA- rron or nmwami:

Application filed June 4, 1928. Serial No. 282,844.

This invention relates to dowser control I mechanism for motion picture projecting machines.

It is intended for use in an electric circuit in which there are placed in parallel a plurality of safety switches which operate to break the magnet circuit when the film of the projecting machine becomes broken or clogs, or

when the motor fuse blows out, or when the 1 transmission beltin of the motor breaks.

The control mechanism operates to drop the dowser into light obstructing position and to sto the motor which feeds the film in case an o the above mentioned difficulties arise. 15 gwitches of the kind just mentioned are to a certain extent standardized today and their construction and method of operation are no doubt well known to those skilled in this art. The object of the invention is to provide a go cheap, simple and efficient dowser control mechanism. v

According to the invention the dowser control mechanism is mounted in a casing which has a shaft journaled therein and upon which 18 the dowser is fastened outside the casing, a magnet, a keeper, a pinion on the shaft, means connecting said keeper and meshing with said pinion for holding the dowser out of light obstructin position when the magnet to is energized, a m feeding motor switch in said casing, and means on said shaft for opening said switch when the magnet is deenergized and the dowser drops into light obstructing position.

The drawings illustrate an embodiment of the invention and the views therein are as follows v Figure 1 is a vertical sectional view taken through the casing hlthough a part of the dowser is shown in full,

Figure 2 is a rear vlew of the mechanism withthe cover removed and looking in the direction of the arrow A in Figure 1 and Figure 3 is a cross-section of the complete apparatus showing the dowser in a raised position and may be said to be taken on a line which is fairly indicated by 33 in Figure 1.

The dowser control mechanism is contained in a casing 11 which has an integrally formed 5 foot 12 for mounting the same upon a cone .36 in said arm.

of the lamp housing (not shown) of a motion picture projectin machine.

The method attachment is shown to be by the screws which pass through holes 14 but it will be understood that while the cone 55 forms a suitable support for the apparatus, it is shown thereon merely as a convenient means of support and the articular foot illustrated may be eliminate and any form of mounting may be used.

The casing has a cover 16 which completely encloses the operating mechanism therein and this cover has a bearing 17 formed integrall therewith for the purpose of housing a she t 18 which extends through said casing and 55 through a bearing formed on the front wall 21 of said casing, and a dowser arm 22 is fixed to the end of the shaft b a set screw 23 which passes through the shanh 24 and through said shaft. 70

The dowser arm extends below the shank 24 and is formed for supporting on each side thereof a plate 26, which platesoare secured thereto and to each other by the rivets or other fastenin means 27. 7

The front 0 the casing 1.1 is provided with an integrally formed stop 28 against which the dowser arm 22 is adapted to strike to limit the upward movement of the dowser.

The upper end of the dowser arm is ro- 30 vided with anoperating handle 31 whic is pivotally mounted at 32 and has an inwardly projecting latch 33 which is urged downward by the spring 34 fastened to the screw The downward movement of the latch 33 is limited by the shape of the socket in which; the handle is pivotally mounted.

The upper end of the casing is provided at its front with an inclined surface 37 beyond which is a notch 38 for receiving the latch 33 on the operating handle 31 and beyond this notch is a shoulder 39 for limiting the movement of the dowser arm.

Fitting within the casing and adjacent to the end wall 21 is a mounting plate 41 which is fastened thereto by screw and upon which a magnet 42 is obliquely mounted by the bracket 43. Between the end wall 21 and mounting plate 41 is a sheet of insulating ma terial 45.

This magnet has a keeper 44 which is fastened to the long leg of a substantially J- shaped plate 4-6 and the other end of said plate is fastened by the screws 47 tothe side face 48 of the gear segment 49. This gear segment meshes with a pinion 51 mounted on the shaft 18 and secured thereto by the pin 52. The gear segment 49 is rotatably mount ed on a bolt 53 which extends through a positioning collar 54 and through the end wall of the casing where it is retained by means of the nut 56.

The shaft 18 is provided with insulating collars .37 and 58 between which is the finger 5f) fastened to the shaft by the pin 61, and this linger is formed of insulating material and is adapted .to engage a spring contact 62 fastened by its one end to tiie'insulating mounting (it) by the screws (55 and nuts 63 and having on its other end a contact point 6a which engages the contact point 66 on the contact arm 67 which is secured by its one end to the insulating mounting 60 by the screw 65 and nuts 68. The screws (55 hold the insulating mounting in the casing.

The casing is provided with a standard approved cable clamp 69.

The nuts (33 and 68 form binding posts for fastening the switch into the motor circuit.

The operation of the dowser control mechanism is as follows The motor for feeding the film mechanism is started by the operator when he presses downward on the operating handle 31 so as to disengage the latch 33 from the notch 38 and then turns the dowser arm slightly so that it will approach the position shown in Figure 3. The motor is started as soon as the shaft rotates sufficiently to disengage the finger 59 from the contact arm 62 to permit contact between the contact points 64 and 66. This starting of the motor is accomplished when the dowser is moved a short distance from its initial position and it is prcsumed that it will be running at full speed when the dowser is completely opened.

\Vhen any one of the safety switches which operate in the event of defective filming, as mentioned in the early part of this specification, breaks the circuit into which the magnet is connected by its wires 71 and 72, the magnet will he deenergized and will release its hold on the keeper 4% and the weight of the dowser will cause it to fall by gravity until it rests in a position such as shown in Figure 2 with its latch retained in the notch 38.

During the dropping of the dowser, the shaft 18 will rotate, thus rotating the pinion 51 which is meshed with the gear segment 4!), and the finger 59 will he rotated so as to press the spring contact arm 62 outward to break the contact between the contact points (34 and (36. This will break the motor circuit.

It will be seen that when the magnet is energized. it will hold the keeper 44 firmly thereon and will prevent the rotation of the gear segment 49 and the finger 59 will thus he held out of contact with the contact arm 62 so as to prevent the breaking of the circuit formed by the contact points (34 and (36.

Of course, the control mechanism illustrated may he modified and changed in various ways without departing from the inven' tion herein set forth and hereafter claimed.

The invention is hereby claimed as follows.

I claim 1. Dowser control mechanism comprising a casing, a shaft journaled in said casing, a dowser fixed on said shaft at right angles to the length of said shaft, a magnet, a keeper, and a gear segment on said keeper meshing with a gear on said shaft for holding said dowser out of light obstructing position when the said magnet is energized.

2. Dowser control mechanism comprising a casing, a shaft journaled in said casing, a dowser fixed on said shaft at right angles to the length of said shaft, a magnet, a keeper, a gear segment on said keeper meshing with a gear on said shaft for holding said dowser out of light obstructing osition whenthe said magnet is energize and means for opening the film feeding motor circuit when said magnet is de-energized.

3. Dowser control mechanism comprising a casing, a shaft journaled in said casing, a dowser fixed on said shaft at right angles to the length of said shaft, a magnet, a keeper, a pinion on said shaft, and a gear segment secured to the keeper and meshing with said pinion for holding said dowser out of light obstructing position when said magnet is energized.

4. Dowser control mechanism comprising a casing, a shaft journaled in said casing, a dowser fixed on said shaft at right angles to the length of said shaft, a magnet, a keeper, a pinion on said shaft, a gear segment secured to the keeper and meshing with said pinion for holding said rlowser out of light obstructing position when the said magnet is energized, and means for opening the film feeding motor circuit when said magnet is deenergized.

5. Dowser control mechanism comprising a casing. a shaft journaled in said casing. a dowser fixed on said shaft at right angles to the length of said shaft, a magnet, a keeper, a pinion on said shaft. and a gear segment pivotally mounted and secured to said keeper, said gear segment meshing with said pinion and held against rotation by the influence of the magnet upon the keeper when said magnet is energized for holding said dowser out of light obstructing position.

(3. Dowser control mechanism comprising a casing. a shaft journaled in said casing, a

Queue 3 dowser fixed on said shaft at right angles to the length of said shaft, a magnet, a keeper,

a pinion on said shaft, a gear segment pivotally mounted and secured to said keeper, 5 said gear segment mesh with said pinion and held against rotation y the influence of the magnet upon the keeper when the said magnet is energized for holding said dowser out cf 11'. ht obstructing position, and means carried y said shaft for opening the film feeding motor circuit when said magnet is de-energized.

In testimony whereof I have signed my name to this specification.

15 JOSEPH T. FEWKES. 

